BrainPoP  -  Animated Science, Health, Technology, Math, Social Studies and English movies, comic strips, activity pages and school homework help for kids. 

IKnowThat.com - Offers web-based educational activities for kids ages 2-12. Activities include stickerbooks, simulation games, painting, math and phonics.  You need to register for a free username and password.

                                                              

PBS Kids - Play hundreds of free educational games and fun activities with your favorite characters from PBS KIDS shows.

Second Grade Skill Builders  - Interactive Math and Language Arts Activities for Second Graders.
                                                                     

Fun Brain - Interactive, educational games (math, grammar, science) for children and kids of all ages.

Brain Teasers - Interactive Math via Houghton Mifflin for Second Graders.